1. Field
Exemplary embodiments of the present invention relate to a light emitting diode and, more particularly, to a light emitting diode having a plurality of light emitting units.
2. Discussion of the Background
Light emitting diodes are widely used for display devices and backlight units. With low power consumption and long lifespan as compared with existing incandescent lamps or fluorescent lamps, light emitting diodes have expanded application ranges to general lighting by replacing existing incandescent lamps, fluorescent lamps, and the like.
A light emitting diode may be driven by forward current and thus repeats on/off operation according to a direction of electric current provided under an alternating current (AC) source. Thus, when the light emitting diode is directly connected to the AC source, the light emitting diode may not continuously emit light and may be easily damaged by reverse current. Moreover, a single light emitting diode may be driven by a predetermined forward voltage and thus may not be driven under high voltage conditions.
A light emitting diode capable of being driven under high voltage AC conditions has been developed. Such a light emitting diode may include a plurality of light emitting units having a substantially square or rectangular shape and connected to one another in series by interconnection wires, and thus, the light emitting diode may be driven by high voltage. Further, a serial array of light emitting units may be connected to a rectifier circuit such as a bridge rectifier, thereby providing a light emitting diode which may be driven by an AC source.
However, a typical light emitting diode having a plurality of light emitting units may have relatively low luminous efficacy.
Korean Patent Publication No. 2011-0024762A discloses a technique for improving light extraction efficiency, in which a convex-concave pattern is formed on a substrate as in a patterned sapphire substrate (PSS), such that semiconductor layers may be grown on the convex-concave pattern. However, this technique has a limit in improving light extraction efficiency only through formation of the convex-concave pattern.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.